2002 Ford Explorer Tranny

I got my transmission re-built ago 5 months ago. About 2 weeks after I got it back it started to do this chattering thing. (Like a vibration) When I drove it for about an hour to TN the overdrive light came on and the vibration got worse. Well the second time I took it to TN it really acted up. The transmission started spewing out fluid from under the car and smoking. I took it to a shop and they said that the fluid was already turning color dark. I was told that it may be becasue the Tannny was getting to hot after it is driven for a while. I was then told to get an external cooler. I found out that I had already had one on and it is working properly. Well now the truck wont even go when I put it in drive or any other gear. It only rives up. Yesterday it was delaying and now it wont move. I have a 2002 Ford Explorer xlt with 170,000 miles on it. This transmission was just put in in August.